One of the child's safety belt connection buckles in the prior art comprises an inserting base with an inserting space and a belt buckle, the belt buckle being capable of inserting into the inserting space along the horizontal direction and being locked by means of a locking mechanism. For instance, the safety belt buckle disclosed by Patent of Publication No. CN202907985U, comprises an inserting base, a base mounted within the inserting base and having an inserting space, a left plug and a right plug for connecting the safety belt and detachably inserted into the inserting space of the base, a locking device for locking the left plug and the right plug within the base when the left plug and the right plug being inserted into the base, a push-out member provided within the inserting space of the base and rotationally connected to a pin shaft, the pin shaft being moveably provided on the base, and an end of the pin shaft extending beyond the base to connect with the locking device, and the locking device being controlled by the push-out member and possessing a locking state and an unlocking state. The push-out member may rotate, and may achieve the lock of the lock device only when the left plug and the right plug both are inserted into the base. When only one plug is inserted, the push-out member rotates, the pin shaft may not move, and the locking device cannot be locked. This prevents the situation that the lock happens when only one plug is inserted, and avoids the existing potential safety hazards when installing the child safety seat.